Communication networks having multiple points of presence (sometimes referred to as base stations or access points) are known. For example, multiple Layer 2 points of presence are available when a communication network has a plurality of wireless access points. As another example, multiple Layer 3 points of presence become available when a communication network has a plurality of access routers as are also known in the art.
In many cases such networks are designed to accommodate mobile nodes that change their location from time to time (including during a present communication session). As a result, a given mobile node can change its point of presence with respect to such a network. For example, a change with respect to a Layer 2 point of presence will occur when the mobile node moves between Layer 2 base stations or access points on a same Internet Protocol (IP) subnet while a change with respect to a Layer 3 point of presence (as well as with respect to a Layer 2 point of presence) will typically occur when the mobile node moves between different anchor nodes or when a mobile node moves between access points connected to different subnets
As is known in the art, when an IP capable mobile node moves from one subnet to another it needs to acquire a new topologically correct address. In a system employing a mobile internet protocol (MIP), the mobile node sends its Care-of-Address (CoA) to its home agent (sometimes referred to as a home anchor node) through the target subnet to enable the home agent proxy for the mobile node and tunnel packets destined to mobile nodes home IP address to the current location, i.e. its CoA.
When moving between multiple points of presence, it is generally desired to make such a move in the least amount of time possible to ensure continuous communication between the mobile node and its anchor node or home agent. The messaging required to facilitate such a movement between subnets generally takes a longer period of time than is desired. Because of this, a need exists for a method and apparatus for handing over of a mobile node amongst such points of presence that minimizes the amount of time it takes to hand over the node.